Genetics and Drug resistance

Question 1

Plasmid-mediated Drug Resistance

Answer 1

Genes on Plasmid code for enzymes that modify the drug

Question 2

Agents modifying proteins

Answer 2

Use on Naked capsid viruses

1. Chlorine
2. Iodine and iodophors
3. Hydrogen peroxide
4. Heavy metals (silver and mercury)
5. Ethylene oxide
6. Formaldehyde

Question 3

Generalized transducting phage

Answer 3

1. When the phage with a lytic life cycle puts a piece of bacterial DNA into its head
2. All bacterial genes have an equal chance of being transduced

Question 4

Ab that undergo Plasmid-Mediated Mechanism of resistance

Answer 4

1. Penicillin and cephalosporins
2. AG
3. Chloramphenicol
4. Tetracyclines
5. Sulfonamides
6. Vanco

Question 5

Three major roles of Site-Specifc integration

Answer 5

1. Integration of Fertility factor to make an Hfr cell
2. Integration of temperate phage DNA to create prophage
3. Movement and insertion of transposons

Question 6

What stabalizes bacterial DNA

Answer 6

Homologous recombination

Question 7

Penicillin/cephalosporin mechanism of resistance

Answer 7

Plasmid-Mediated

Production of β-lactamase

Question 8

Enzymes required for Homolgous Recombination

Answer 8

1. recA
2. recB
3. recC
4. recD

Question 9

Site-Specific Recombination

Answer 9

Is integration of one DNA molecule into another DNA molecule with which it has no homology

Question 10

What controls Conjugation

Answer 10

Fertility factor in plasmid or episome

Question 11

Chloramphenicol mechanism of resistance

Answer 11

1. Plasmid-mediated
2. Production of acetyltransferases leading to inactivation of drug by acetylation

Question 12

Transposons are

Answer 12

• Mobile genetic elements that can move themselves or a copy from one molecule of DNA to another
• Have sequences of indirect repeats of bases
• Creat additional mutations with their insertion
• Insertion creats direct repeats

Question 13

Transformation

Answer 13

Naked DNA is taken up by the cell

Question 14

Endonucleases

Answer 14

Cleave the nucleic acid backbone in the middle of the NA strand

Question 15

Aminoglycosides mechanism of resistance

Answer 15

• Plasmid-mediated
• Production of acetyltrasferases, adenosyltransferase, or phosphotransferase that inactivage the drug via acetylation, adenosylation, or phosphorylation

Question 16

Intrinsic Drug Resistance

Answer 16

• Lack the target molecule for the drug
• Normal anatomy and physiology of bacteria makes them refractory to the drug action

Question 17

Autoclaving control

Answer 17

15 lbs pressure at 121^oC for 15-20 min

Question 18

Chromosome-mediated Ab resistance

Answer 18

Genes on bacterial chromosome that modify the receptor for a drug so that the drug can no longer bind

Question 19

Site-Specific Recombination requires

Answer 19

Restriction endonucleases

Question 20

Agents damaging membranes

Answer 20

Use on Viruses

1. Detergents
2. Alcohols
3. Phenols

Question 21

Conjugation

Answer 21

Cell to cell contact

Question 22

Transduction

Answer 22

Bacteriophage pick up and carry bacterial DNA

Question 23

Natrual transforming bacteria

Answer 23

1. H. influenzai
2. S. pneumoniae
3. Bacillus
4. Neisseria

Question 24

Exonucleases

Answer 24

Remove terminal nucleotides sequentially from linear pieces of DNA

Question 25

COBEDS

Answer 25

Phage-Coded pathogenic Factors via Lysogenic Conversion

• Cholera toxin
• O antigen of Salmonella
• Botulinum toxin
• Erthrogenic exotoxins of S. pyogenes
• Diptheria toxin
• Shiga toxin

Question 26

Specialized transduction

Answer 26

• Error is made in the life cycle of a templage (lysogenic) phage
• Temerate phage introduce their genomic DNA into the bacterial chromosome at a specific site